'Flesh-eating' bacteria strain spread by sneezes and coughs

London
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Medical experts in the UK have warned the public to be vigilant about their health to guard against infection by a highly infectious strain of MRSA called USA300, that causes a deadly form of pneumonia, skin boils and abscesses.

The deadly bacteria can be easily passed between people in public places through sneezes and coughs and through contact with the skin of an infected person.

Metro reports Professor Chris Thomas, professor of molecular genetics at the University of Birmingham, said: "If you’re on a crowded tube or bus and you sneeze you can spread the bacteria. But your sneeze can also land on a metal surface and when someone else gets up from their seat and steadies themselves on the hand rail they can catch it. However, MRSA is also prevalent in the nose and the hair so might be spread by scratching the head and then shaking hands."

The MRSA strain is called USA300 because it was first reported in the United States.

Daily Mail reports Dr. Ruth Massey of the Department of Biology and Biochemistry at the University of Bath, has warned that people need to take extra care with the USA300 strain and similar types of strains known as PVL-positive community-acquired strains.

Medical experts say USA300 is resistant to several front-line antibiotics, that is, antibiotics of first-choice in the event of infection. The bacteria is called "flesh-eating" because infection leads to large unsightly boils and abscesses on the skin and can lead to fatal blood poisoning, or a dangerous form of pneumonia that destroys the lung tissues.

Community-acquired MRSA vs hospital strains

According to Massey, 1,000 cases of PVL-positive community acquired MRSA were reported in England last year. Out of these, 200 were caused by the "flesh-eating" USA300 strain. The medical expert said: "These community-acquired strains seem to be good at affecting healthy people. They seem to be much better than the hospital ones at causing disease.They don't rely on healthcare workers moving them around, which the hospital ones seem to."

Metro reports Professor Chris Thomas, said: "[they break] down tissue...get into your heart, bacteria can get into your bloodstream and take hold of different parts of your body. That could lead to death quite easily."

Massey said while USA300 has become a major problem in the U.S., experts in the U.K. have had foreknowledge of the bacteria and are working to contain its spread.

Massey and her colleagues published a new research paper in the Journal of Infectious Diseases in which they did an analysis of the way community-acquired strains adapt and spread outside hospital environment. According to the researchers, community-acquired strains are different from hospital strains. Community-acquired MRSA strains, according to the experts, have cell walls that are not the same as those in hospitals. The adaptation of their cell walls makes them able to sense their environment and switch on toxin production when it is needed.

Daily Mail reports Justine Rudkin, a PhD student involved in the studies, said: "The community-acquired bacteria has evolved further, and is able to maintain a higher level of toxicity while also resisting treatment from antibiotics, making it a much larger problem."

Massey and her colleagues found that hospital MRSA bacteria have remained largely confined to hospital premises and have not been able to spread out effectively. She said: "Our research found that the composition of the cell wall of the bacteria is critical to the community-acquired bacteria being more toxic. The ability of the MRSA bacteria to secrete toxins is one of the main ways it causes disease. Using a sensing system, it carefully controls when it switches on its ability to do this, so as not to cause disease until it is firmly established within the human. Many antibiotics target the cell walls of harmful bacteria, and to resist this, the bacteria have to make changes to their cell wall."

Experts:'Community-acquired strains better at infecting the young and healthy'

PHYSorg.com explains that the hospital strains cause disease in hospital patients who are already weakened by illness. Medical institutions have in recent years been making progress in controlling the hospital strains. They are now concerned about the emergence of the community-acquired strains which attack young healthy people.

Thomas said that community-acquired strains are better at infecting young and healthy people because, unlike the hospital strains that are exposed to powerful drugs and disinfectants, community-acquired strains have not invested genetic resources to developing resistance to man-made agents. They are, therefore, able to develop more powerful disease causing toxins. He warned that people need to be extra vigilant about their health and stop abusing antibiotics.

A spokesperson for the Health Protection Agency (HPA), said the study by Massey and her colleagues has helped in understanding, "at the molecular level why hospital strains of MRSA are less virulent than the so-called community MRSA strains. We have known about community MRSA for over a decade and, whilst they are responsible for a high burden of disease in North America, this is not the case in the rest of the world. In England we have seen sporadic cases of this type of MRSA most often causing boils and abscesses, but it has not emerged as a major public health issue in this country.The HPA are carrying out active surveillance of this type of bacteria and advise healthcare professionals on correct infection control procedures to reduce the likelihood of spread."